SINGAPORE - Trains on the 30-year-old North-South Line were stopped for about seven minutes during passenger service hours on Thursday (March 30) nigh for the second trial of a new communications-based train control system by the Land Transport Authority and train operator SMRT.

The new signalling system will allow trains to run 100 seconds apart instead of the 120 seconds of the existing fixed-block signalling system - an upgrade that may help alleviate the rush-hour crushes that have plagued commuters of late.

However, no date has yet been set for the replacement of the old system with the new.

The first trial had taken place on Tuesday (March 28), when trains stopped for about 10 minutes from 11.10pm to 11.20pm while the new signalling system was activated.

SMRT said in a Facebook post on Thursday evening (Mar 30) that that trial had been "successful".

When The Straits Times arrived at Bishan MRT station at about 10.30pm on Thursday night, automated announcements in the four languages were already informing passengers that platform and train doors would be controlled automatically by the new system from 11pm onwards, and cautioning them not to rush aboard.

It finally happened at 11.13pm - the train that pulled into the northbound platform stayed put for seven minutes as station staff announced the switch-over.

But commuters were hardly in a rush at this hour - most were engrossed in smartphone screens or listening to music. Passengers sauntered through the doors. A man read the evening paper. The train was slightly fuller than the previous one but not jam-packed.

Nevertheless, SMRT staff distributed vouchers for free train rides to commuters waiting on the platforms as a gesture of goodwill.

By 11.20pm it was over. Life returned to normal on the North South Line as trains resumed their arrivals at four-minute intervals.